Domestic heating system



Dec. 14, 1965 J. LETOURNEAU DOMESTIC HEATING SYSTEM 4 Sheets-Sheet 1 Filed Feb. 20, 1964 FPO/14 ZG/VE 7 /A/Vf/VTDR Jac qu es L E TOUR/VEAU ATTOR/VE Y5 1965 J. LETOURNEAU 3,

DOMESTIC HEATING SYSTEM Filed Feb. 20, 1964 4 SheetsSheet 2 IIYVE/VTOR Jizcyue s L F r MIRA/[AU Dec. 14, 1965 J. LETOURNEAU 3,223,325

DOMESTIC HEATING SYSTEM Filed Feb. 20, 1964 4 Sheets-Sheet 5 /IVVIVTOR Jdrya e 5 L ETUURIW AZ/ B) A rromvns Dec. 14, 1965 J. LETOURNEAU 3,223,325

DOMESTIC HEATING SYSTEM Filed Feb. 20, 1964 4 Sheets-Sheet 4.

INVEWTOR Patented Dec. 14, 1965 3,223,325 DOMESTIC HEATING SYSTEM Jacques Letourneau, 20 Ave. Beaumont, Quebec, Quebec, Canada Filed Feb. 20, 1964, Ser. No. 346,190 20 Claims. (Cl. 2369) This invention relates to domestic heating systems, and more particularly to a heating system for dwellings comprising a number of substantially independent zones having differing heating requirements which must be supplied from a common furnace.

As is well known in the domestic-heating art, the adequate heating of a dwelling is by no means a simple problem, even in relatively small dwellings. It will be obvious that different zones of the dwelling will require differing amounts of heat, depending on the relative sizes of the various rooms, the amount of window space therein, whether said windows are subjected to sunlight or shadow, etc. Moreover, apart from such considerations of the quantity of heat required, it will be realised that different zones of the dwelling may also require difierent temperatures. For instance, the bathroom and bedroom may require to be kept at a higher temperature than the livingroom, whereas the kitchen may be regulated to a lower temperature since it already receives a considerable amount of heat from the kitchen stove. Basements have always proved difficult to keep adequately warmed and dry, whereas the top floor of a multi-level dwelling tends to become excessively warm due to the natural convection current from the lower levels and to solar radiation striking the roof of the dwelling.

Economic considerations generally dictate that the entire dwelling must the heated from a single furnace, and the contemporary heating systems intended to achieve this are often rather rudimentary, taking little if any cognizance of the said tendency of heat to rise from the lower levels, or of the different temperatures demanded by the various zones according to their respective functions. Moreover, although the furnace is generally shut off upon arrival of the Spring season, the basement frequently requires heating for several months longer if it is to remain at all habitable. However, with present heating systems the furnace cannot be started to warm up the basement, without also causing the remainder of the dwelling to become excessively warm.

Accordingly, it is an object of the instant invention to provide means whereby a contemporary furnace and heating duct system may be rendered much more selective in ope-ration, without, however, entailing extensive modifications thereto.

It is a further object of the invention to greatly enhance the flexibility of conventional heating systems, while yet retaining a relatively simple and economical control system therefor.

It is a further object of the invention to provide means whereby the essentially discrete zones of a dwelling may be individually heated in accordance with their respective requirements.

It is another object of the invention to ensure that the basement of a dwelling can be warmed sufficiently to be habitable all year round, without, however, causing excessive heating of other zones of such dwelling.

Another object of the invention is to provide means whereby the supply of heat from a central furnace may be diverted to individual zones of a dwelling, either singly or in any desired combination.

Briefly my invention contemplates providing each discrete zone of a dwelling with an individual thermostat, which is arranged to open a motor-driven trap door, or bafile, connecting said zone to the hot air supply duct of the furnace. The invention also provides a system 'of interlocks to ensure safety of operation and to enable the heating requirements of certain zones to be given preference if desired.

For a further appreciation of the aims and objects of the present invention, reference should be made to the ensuing disclosure and associated drawings wherein:

FIG. 1 is a partially sectioned perspective view of a conventional furnace which has undergone modification in accordance with the invention;

FIG. 2 is a plan view of the furnace of FIG. 1;

FIG. 3 is a sectional view of ducting taken on the line 33 of FIG. 2;

FIG. 4 is a schematic diagram of the circuitry employed to control the furnace of FIG. 1 in accordance with the heating requirements of a bungalow type dwelling;

FIG. 5 is a perspective view of a furnace similar to that of FIG. 1 when modified for heating of a multi-level dwelling;

FIG. 6 is a schematic diagram similar to FIG. 4 of circuitry suitable for controlling the furnace of FIG. 5.

Dual-zone embodiment Referring now more particularly to the drawings (in which like reference characters indicate like elements throughout, normally closed contacts being denoted by the character a, and normally-open contacts :by [2), the heating system according to the present invention comprises a furnace 1 having an inlet manifold 2 and an outlet manifold 3 mounted thereon. The inlet manifold 2 connects with various ducts such as 2a and 211, through which relatively cool air is drawn into furnace 1. Such relatively cool air is continuously being displaced from the various zones being heated by the considerably hotter air emanating from similar ducting 3a, 3b, 30 connected to the outlet manifold 3 of the furnace 1. In the particular embodiment which has been illustrated in FIG. 1, the inlet duct 2a is employed to draw cool air from the upstairs zone of a bungalow, whereas inlet duct 2b is employed to induct cool air from the basement zone of the bungalow. Similarly, the outlet duct 3a is employed to convey hot air to the upstairs zone from outlet manifold 3, and a duct or vent 3c is generally provided in said outlet duct 3a to admit a modicum of hot air to the basement zone. However, such an arrangement renders warming of the basement possible only during periods when hot air is :being supplied to the upstairs zone of the dwelling via duct 3a. Therefore, in order that the basement may receive an adequate supply of warm air even when no heating is required in the upstairs zone, an alternative outlet duct 3b is provided connecting the hot air outlet manifold 3, direct to the basement zone. The alternative hot air duct 3b may therefore be used to provide heating of the basement in the Spring season when heating is not normally required upstairs through duct 3a.

Suitable baffling Z may be employed in the respective delivery and return ducts 3a, 2a to close olf the air circulation path through the upstairs zone, which will henceforth be referred to as zone 2.. A similar baffle Z may be employed to open the air circulation path via respective delivery and return ducts 3b, 2b through the basement zone, which will henceforth be referred to as zone 1. An actuator motor M may be employed to drive baffling members Z' Z to their respective positions shown in FIG. 1, through any convenient mechanism such as a chain and sprocket drive or alternatively, the crown and pinion type gearing 4, 4' shown. The actuator motor M is preferably of the torquemotor type having a unidirectional drive with a spring-return for resetting the rotor to its initial position when the motor is switched off, so that baffle Z' will open the air exchange path through zone 2 and baflle Z will assume its closed position to shut off the air exchange path through alternative duct 3b to the basement zone Z' A suitable type of actuator motor M is the electro-hydraulic torquemotor sold by the Minneapolis Honeywell Company under catalogue number M828C.

The furnace 1 may be of any conventional type such as an oil-burner of adequate thermal capacity comprising a burner B (FIGS. 2 and 4) maintaining the flame of combustion within a combustion chamber or firepot C (FIG. 4). The furnace 1 is also provided with a fan F which directs the cool air received through the intake manifold 2 against the redhot firepot C, thereby to both cool said firepot to prevent melting thereof and to raise the air to a suitable temperature for entry to the output manifold 3 of the furnace.

Dual-zone Operation Considering now the circuitry whereby the heating apparatus of FIG. 1 is cont-rolled, FIG. 4 illustrates the baffle actuator motor M in the activated position of FIG. 1, wherein baffle Z is in its open position, bafile Z g being closed as shown. The sequence of events by which baffles Z Z are driven from their reset position (shown in phantom in FIG. 4) to their activated position (illustrated in FIG. 1, and indicated by the solid line at A in FIG. 4), will be explained with respect to FIG. 4 as follows:

Assume for purposes of explanation that all equipment has been switched off, whereby the entire dwelling is relatively cool. Zones 1 and 2 of the dwelling are provided with respective thermostats T1, T2 connected in sensor loops Z Z which also have respective relays R R serially inserted therein. Position-responsive switches p p may be connected in either manner shown in FIG. 4, whereby they are capable of inhibiting the sequence of events normally initiated by T T The respective loops Z Z of the thermostatic sensor circuits may be energized from any suitable source s of electrical energy, such as a common 110 volt mains. The burner circuit L comprises a loop connecting the burner B with a suitable source s of electrical energy through a set of normally-closed protective-monitoring controls P Such protective controls P, may be conventionally arranged to respond to fuel-oil level, fuel-leaks, inflammable vapour content in the atmosphere, etc. and form no part of the instant invention. The burner loop L may be completed through the normally-open contact of a burnercontrol relay R This burner-control relay R is connected in the burner-control loop C in series with a source s of electrical supply across terminals T-T'. The burnercontrol loop C may be completed across terminals TT' through either of a pair of branch circuit-s C C the branoh lo-op C is arranged to be closed by the normallyopen contact b' of relay R whereas the branch loop C is arranged to be closeable through the normally-open con-tact b' of relay R The furnace blower fan F is arranged to be connected across a suitable source s of electrical supply by means of a thermostat T disposed in the region of the firepot C to render it responsive to the temperature of the ambient air thereabout. A relay R is connected in parallel with fan F for operation simultaneously therewith by the hot air thermostat T The sequence of events whereby baffles Z Z are activated from their reset position (indicated in phantom in FIG. 4) to their activated position (as illustrated in FIG. 1 and indicated by the solid-line A in FIG. 4) will now be described with reference to FIG. 4 as follows:

To facilitate the explanation, assume that all circuitry of FIG. 4 has been de-energized, as by disconnection from the electrical supply source 5. Motor M being deenergized, will be reset to its off position indicated in phantom in FIGS. 3 and 4. In thus resetting, motor M also resets the baflies Z Z coupled thereto, whereby the ducts 2a, 3a communicating with zone 2 are open to the phantom position shown in FIG. 3, while simultaneously closing off the alternative duct 312. Such resetting of bafiles Z' Z' brings them into contact with the normally-open position-responsive switch p which is thereby closed.

With the actuator motor M thus reset to its off position assume that source s is re-energized, as by closing the mains-breaker supplying the house. When the Zone 2 (which may be the upstairs region of a house, .as aforementioned) becomes sufficiently cold, the thermostat T reverts to its normally-closed condition, thereby connecting the sensor loop Z to supply s through the (now closed) switch 7 and relay R Relay R thus becomes energized, closing its normally-open contact [2' to complete the branch loop C across terminals T-T of the burner-control loop C. The burner-control relay R is thus connected to the voltage source s via loops C C and contact b of relay R Hence relay R becomes energized and connects burner B to the electrical source s, thus completing the burner loop L through the normally-closed safety-controls P Accordingly burner B ignites and the firepot C rapidly begins to heat. When the ambient air about firepot C becomes :sufiiciently warmed it activates the normally-open thermo- :stat T to closed position, thereby simultaneously connecting both the fan F and the relay R to the electrical source s. Accordingly fan F commences toinduce cool air from inlet manifold 2 over firepot C towards the hot air outlet manifold 3, thereby considerably warming said air while simultaneously inhibiting excessive heating of said firepot C.

Accordingly the hot air proceeds from outlet manifold 3 (FIG. 1) through the delivery duct 3a (FIGS. 1 and 3) and into zone 2. This flow of hot air into zone 2 through the delivery duct 3a will continue until the heat requirements of zone 2 have been fulfilled, whereupon the thermostat T will open in response to the increased temperature of said zone 2, thereby opening sensor loop Z and deactivating relay R thereof. The loop C across terminal T-T' of burner control loop C will thus be broken, de-energizing burner control relay R Consequently the burner loop L will in turn be broken, shutting off burner B. Fan F will, however, continue to operate, as T will remain closed due to the continuing presence of hot air about the still-hot firepot C. This continuing operation of fan F will, however, eventually cool firepot C sufliciently to cause thermostat T to revert to its normally-open condition, thereby shutting off fan F and also de-energizing the relay Rf (whose purpose will be explained hereinafter). In such manner the heating of zone 2 may readily be accomplished by means of the instant invention.

The manner in which the circuitry of FIG. 4 may also provide convenient heating for a further zone 1 (such as a basement) will now be described:

Assume now that while zone 2 has been heating as above described, the zone 1 (which may be the basement region of a house as aforementioned) has been becoming progressively colder. Such a state of affairs is likely, due to the natural tendency for convection currents to rise from lower to higher levels within a building, thereby inducing leakage of cold air into the lower levels from the exterior of the dwelling. It is to be recalled, moreover, that all equipment is now essentially in deenergized condition, thermostat T having opened in desponse to heating of zone 2, thereby dropping out relays R R and thus burner B and fan F, etc. Accordingly, when basement zone 1 becomes sufficiently cool, the normally-open thermostat T closes its associated sensor loop Z through source s, thereby energizing relay R This causes normally-open contact b" of relay R to close and complete motor-loop L through the starting loop S (which contains respective normally-closed contacts a of relays R R whereby motor M becomes energized from a source s and commences to drive bafiies Z' Z to their activated positions (as illustrated in FIG. 1 and indicated at A in FIG. 4) against the restraining action of the resetting mechanism (not shown). Meanwhile, said energization of relay R has also closed another normally-open contact b' thereof, thereby placing a branch loop C in standby condition, merely awaiting closure of normally-open switch p to effect completion of said branch C across terminals TT' of bumer control loop C. Consequently when motor M (now energized through contact b" of relay R drives baflies 2' (and thereby 2' to their activated position (shown in FIGS. 1 and 3 and at A in FIG. 4) the normally-open switch P (shown in FIGS. 3 and 4) is closed by contact with said bail-ling. Thus the branch-loop C is completed through position-responsive switch p and relay contact b' across terminals T-T of burner circuit C, thereby energizing burner-control relay R Burner loop L is there by closed and burner B consequently ignites to heat firepot C. Ambient-air-temperature thermostat T thereupon starts fan P, which induces cool air from zone 1 through inlet duct 2b into inlet manifold 2 and thence over firepot C, which thereby becomes cooled while heating said air for passage into outlet manifold 3 and out through alternative duct 3b to warm the basement zone 1. It is to be recalled that fan-responsive relay R becomes energized simultaneously with fan F, and has thus broken starting loop S, by opening its normally-closed contact a while closing its normally-open contact b to establish a holding loop H; to maintain the motor loop L Motor loop L thus remains intact through contact a of relay R normally-open switch p' (now closed by battles 2' 2' and contact b of relay R whereby motor M continues operating to maintain baffies 2' 2' in their activated position A.

The above-described situation persists until the heating requirements of zone 1 (the basement) have been fulfilled, whereupon zone 1 attains the desired preset temperature and the normally-closed thermostat T breaks sensor loop Z de-energizing relay R whose contact b reverts to its normally-open condition, thereby breaking branch-circuit C across terminals T-T' of burner-control loop C and de-energizing relay R The burner-control relay R thus drops out its contact, opening burner loop L whereby burner B shut ofi. Fan F however, continues operating, and relay R; thus continues to hold in its contact b to keep motor M operating. Keeping M operating prevents T from energizing R until fan F shuts oif. Since burner B is now switched oif, fan F is soon able to cool firepot C down to a temperature at which its ambientair thermostat T reverts to the normally-open condition, whereat fan F and relay R are simultaneously deenergized. As relay R; drops out, its contact b reverts to its normally-open position thereby breaking holdingloop H to shut otf motor M Consequently motor M is immediately reset by its bias-spring to the phantom position of FIGS. 3 and 4, and the entire system is once again on standby condition, awaiting any demand by thermostats T T for heating of their respective zones 1 or 2.

It will be noted that, in the event of simultaneous demand for heating by thermostats T T the zone 2 will receive priority since once relay R ecomes energized its normally-closed contact a becomes opened to break motor-loop L and maintain motor M de-activated for as long as relay R remains energized. Motor M also cannot start for as long as R remain energized by the action of fan F. Thus any simultaneous demand from T is ignored since motor M cannot start and therefore position-responsive switch 2 cannot be closed by bafiles Z' Thus branch-loop C remains open, terminals TT' being interconnected via the other branch-loop C by (now closed) contact b of relay R which became energized upon demand of thermostat T of zone 2.

It should be realized that it is necessary to have an air-circulation path through the furnace 1 at all times, since in the absence of such air exchange the fan F is liable to stall and/or firepot C is liable to become overheated sufiiciently to become burnt or melted. It is for this reason that position-responsive switches p p are incor-porated in the respective branches C C; (at loop Z of burner-control circuit C, whereby burner-control relay R cannot become energized until bafiles 2' 2' have actually reached their intended positions. The presence of normally-open switches p p thus prevent operation of the burner B in the event of jamming of the baflles, breaking of the resetting mechanism opposing motor M etc.; or a similar normally-open position-responsive switch p may be inserted in the holding loop H in order that the latter may also remain broken following any mechanical failure of the baflles.

The holding circuit H only becomes energized following a demand for heating in zone 1. It will be noted that once the demand of zone 1 is satisfied the relay R is deenergized and allows its contact b" to open starting loop S which would proceed to break the motor loop L and thus stop motor M This would allow resetting of the bafiles while fan F was still attempting to cool firepot C, and the resulting disturbance of the air-exchange path may either damage the battles or choke off the supply of cool air to fan F, which is not normally rated for operation in warm air. Accordingly, the function of holding loop H is to bypass the starting loop S when the latter is broken by dropout of relay R and thereby keep motor M operating until fan F stops and allows the bafiies to be safely reset. The desired holding" function of loop H is conveniently provided by arranging for said loo H to be closed by a normally-open contact 6 of fan relay R shortly following response of relay R to a demand from T of zone 1. Thus when such demand of zone 1 becomes satisfied and allows relay R to drop out, the fan relay R continues to hold loop H intact through its cont-act b until fan F comes to a stop and thus renders the situation safe for resetting of the battles.

It should also be noted that, since hot air tends torise by convection, the thermostat T should be set to respond to an equal or higher temperature than thermostat T Multi-zone embodiment The heating system of the inst-ant invention as thus far described, may be adapted to dwellings having more than two discrete heating zones, such as the multi-level dwelling shown schematically in FIG. 5. As is seen from FIG. 5, the multi-level dwelling is divided by floors, f f f into at least zones 1, 2 and 3.

The various zones 1, 2, 3 are arranged to have appropriate grills 2:1 2a 2a through which cool air may be extracted from the respective zones. These inlet grills are located adjacent the respective fioors f f f where the coolest air will normally be found, and may be selectively connected to the inlet duct 2a of a furnace 1 by means of baflles (not shown) operated by respective motors M M M Similarly, the individual zones 1, 2, 3 are provided with individual grills 311 3a 3a through which hot air may be introduced to the various zones. These heating grills 3:1 3:1 312 may be selectively connected to the hot air outlet duct 3a of furnace 1 by the opening of respective baffles which may also be arranged to be operated by respective motors M M M through any suitable mechanical linkage (for example a chain and sprocket drive) similar to the means 4, 4 employed in FIG. 1.

M ulti-zone operation The operation of the multi-zone heating system of FIG. 5 will now be explained with reference to the control circuitry of FIG. 6, the heating of zone 1 being accomplished in FIG. 6 in a manner similar to that employed for the heating of zone 1 by the circuitry of FIG. 4, namely:

Upon zone 1 becoming too cold, thermostat T reverts to its normally-closed condition, thereby energizing relay R through the supply source s. In thus picking up, the relay R closes its normally-open contacts b" b' the former of which completes starting loop S to start motor M while the latter contact places branch loop C in standby condition until motor M opens the baffles of grill 3a sufficiently to close normally-open position-responsive switch p As in FIG. 4, closure of switch p completes loop C across terminals T-T' of the burner control loop C, thereby energizing burner control relay R Pickup of R completes burner loop L, and ignites burner B. Subsequently fan thermostat T responds to heating of firepot C and starts fan F as before to direct a stream of hot air from output duct 3a of FIG. through grill 3a into zone 1 until thermostat T again opens to drop out relay R w-hose contact b" reverts to its normally-open position, breaking starting loop S Motor M however, continues in operation through its holding loop H until de-activated by reversion of fan-relay contact b to its normally-open condition upon dropout of its relay R as the fan F ceases operation. A similar sequence of events takes place when heating of either of zones 2, 2 is called for individually.

f, however, T M and F are all in operation (as just described) and another zone (for instance zone 3) becomes too cold, then thermostat T reverts to its normallyclosed condition, picking up R and closing normally-open contact b" thereof to complete starting loop S of motor M Motor M thereupon drives its associated baffles (from their closed position obstructing grills 2e1 311 thereby opening an air exchange path through zone 3, and incidentally closing normally-open position-responsive switch p It will be noted that closure of p completes branch loop C through (now closed) contact b' of R across terminals T-T' of burner control loop C. It will be noted that loop C is, however, already completed through loop C whereby loops C C are now merely paralleling one another across terminals TT of the thus-completed burner-control loop C.

It will be noted that although holding loop H; of motor M is incidentally placed in standby condition by the normally-closed contact a of R (assuming no demand by zone 2) and by the closure of normally-open contact h of Rf (now energized, due to demand by zones 1 and 3); said loop H is nevertheless maintained open by the normally-closed contact a of R (now energized).

Similarly, the holding loop H of motor M is disabled by opening of normally-closed contact a of R (now energized). Thus zones 1, 3 are effectively interlocked (via relays R R to disable the holding loops H H of each others baffle-actuator motors M M so that neither motor can continue operating after demand of its zone has been satisfied (as indicated by dropout of its zone relay R R unless the other motor has already stopped.

The holding loops H H H of all zone motors M M M are mutually interlocked in similar fashion via normally-closed contacts a a a -a a -a of their respective zone relays R R R Thus no individual zone motors M M M can remain operative after dropout of the respective zone relays R R R unless the respective demands of all other zones 23, 3-1, 1-2, have already been satisfied.

Such an arrangement insures that the air-circulation through each zone will be shut off immediately the respective zone thermostat indicates that the desired zone temperature has been achieved. Such progressive isolation of the respective zones will thus continue until only one zone remains unsatisfied (say, for example, zone 2). In such a case R M Rf and fan P will all still remain energized. R R will have completed holding loop H of M (through their respective a contacts, now returned to their normally-closed condition). Thus when the heating requirements of this final zone 2 have been fulfilled, dropout of R (by T will not cause stoppage of M through breaking of starting loop 5;, but M; will continue in operation through its holding loop H pending reversion of fan-relay contact b to its normally-open condition upon dropout of R by T in response to cooling of firepot C. By thus retaining the sole remaining holding loop H intact until fan F has ceased operation, the sole remaining air exchange path (namely that circulating through zone 2, in the case assumed) is maintained open, thereby permitting a flow of relatively cool air to fan F until the firepot region has cooled sufficiently to allow for safe shutoff of fan F and closure of the air circulation path to zone 2.

It will be realised that the heating system of the invention is capable of rendering the basement habitable all year round, including the spring season when the furnace cannot normally be operated without affecting the comfort of the upstairs region of a dwelling. It will, moreover, he realized that the heating system of the invention is not confined solely to heating of the basement or multilevel zones, but may be employed to heat several different zones on the same level, as for example to provide individual heating to the bathroom, bedroom, and livingroom zones respectively of a bungalow. Such a system causes no inconvenience, as such furnaces have very short heating cycles, and can heat a zone completely in a few minutes, before proceeding to heat the next zone experiencing a demand.

While the invention has been illustrated and described with respect to a specific embodiment thereof, it will be realized that the invention is not necessarily limited to heating of two or three zones, and that various analogies and modifications may be resorted to without, however, departing from the spirit and scope of the invention as set forth in the appended claims.

I claim:

1. A heating system comprising a furnace having input and output ducts enabling air interchange between said furnace and at least a pair of discrete zones of a dwelling; each said zone having corresponding baffles interposed between itself and said furnace, bafile o erating means for selectively establishing or preventing said air interchange between any of said zones and said furnace, control means for said baffie operating means comprising a thermostatic sensor loop for each zone, a zone relay responsive to said sensor loop, a motoring loop for each baffie operating means to drive same in response to energization of the respective zone-relay, a holding loop for maintaining said motoring loop after de-energization of said zone-relay, and delay means to break said holding loop after shutdown of said furnace, said means responsive to cooling of said furnace.

2. A heating system comprising a furnace having input and output ducts enabling air interchange between said furnace and at least a pair of discrete zones of a dwelling; each individual zone having corresponding baffles disposed in said ducts for selectively opening or closing said ducts to said individual zone, baffle operating means whereby said baffles may be actuated between alternative positions affecting respectively said opening and closing, a thermostatic sensor loop for each zone, said sensor loop comprising a zone-mounted thermostat and a respective zone-relay energizable thereby, a motoring loop for each baffle operating means to affect driving of same to correspondence with one of said positions, a starting loop completing said motoring loop responsive to energizing of the respective zone relay, whereby said driving occurs, a holding loop whereby said starting loop may be bypassed to maintain said motoring loop after de-energization of said respective zone relay, and delayed relay means to break said holding loop and thus de-activate said motoring loop after shut-down of said furnace, said delayed relay means thermostatically controlled by a predetermined cooling of said furnace following shutdown thereof.

3. A heating system as in claim 1 wherein said bafiie operating means comprise a motor having resetting means,

said motor activating the bafiies of one of said zones to a position wherein said air interchange is established between the furnace and said one of said zones, de-energization of said motor permitting said resetting means to return said baffles of said one of said zones to an alternative position where said air interchange between said furnace and said one of said zones is prevented.

4. A heating system as in claim 1 wherein the baffies of at least two zones are intercoupled to prevent air interchange between one zone and said furnace upon establishment of air interchange between another zone and said furnace.

5. A heating system as in claim 1 wherein the respective bafiies of each zone are uncoupled from those of the remaining zones.

6. A heating system as in claim 4 wherein said intercoupled baffies have in common said baffle-operating means, the motoring loop of said common bathe-operating means being interruptable by the zone relays of both of said two zones, said interruption performed by respective contacts of said zone relays, said contacts located in said motoring loop, said holding loop bypassing one said contact to maintain said motoring loop despite dropout of said bypassed contact.

7. A heating system as in claim 5 wherein each individual zone is provided with bathe-operating means coupled to the respective bafiles of said individual zone, the motoring loop of said battle-operating means of said individual zone having a starting loop shorting said holding loop, said starting loop being interruptable by a contact of the zone relay of said individual zone, said holding loop being interruptable by the zone relays of each of the remaining zones.

8. A heating system comprising a furnace having input and output ducts enabling air interchange between said furnace and at least a pair of discrete zones of a dwelling; battle means within said ducts between each discrete zone and said furnace, said bafile means actuable to an activated position wherein said furnace communicates with one of said zones, from a reset position wherein said furnace communicates with at least another of said zones, actuator means for driving said baflies to said activated position, resetting means for returning said battles to said reset position upon de-energization of said actuator, zone relays controlled by respective thermostats within said zones, 21 motoring loop for said actuator to effect energization thereof, a starting loop completing said motoring loop in response to energization of the zone relay of said one of said zones, a holding loop bypassing said starting loop, and means independent of said starting and holding loops whereby said motoring loop may be interrupted by the zone relay of said another zone.

9. A heating system as in claim 8 wherein said air interchange is effected by a blower fan within said furnace, a fan-responsive relay having respectively a starting contact and a holding contact, said starting contact breaking said starting loop and said holding contact completing said holding loop when said fan is operating.

10. A heating system as in claim 9 wherein a bathe-position-responsive switch is provided in series with said holding contact.

11. A heating system as in claim 8 wherein a battleposition-responsive switch is provided in series with the zone relay of said another of said zones.

12. A heating system as in claim 8 wherein said furnace comprises a burner, a burner loop for connection of said burner to an electrical source, a burner-controlrelay to complete said connection, a burner-control loop for energization of said relay, means completing said burner-control loop responsive to energization of the zone relay of said another of said zones, and means for completing said burner-control loop upon energization of the zone relay of said one of said zones.

13. A heating system comprising a furnace having a burner, a burner loop for Operating said burner, input and output ducts enabling air interchange between said furnace and a pair of discrete zones of a dwelling, a fan for effecting said interchange, bafile means within said ducts between each discrete zone and said furnace, said bafile means actuable to a first position wherein said furnace communicates with the first of said zones from a second position wherein said furnace communicates with the second of said zones, motor means for driving said bafiies to said first position, reset means for returning said bafile to said second position upon shutoif of said motor, zone relays operable by respective thermostats within said zones, a motoring loop for energizing said motor, a starting loop for completing said motoring loop, a contact for closing said starting loop upon pickup of the zone relay of said first zone, a holding loop bypassing said starting loop, a contact for opening said motoring loop upon pickup of the zone relay of said second zone, a relay having a first contact closing said holding loop and a second contact opening said starting loop during operation of said fan, a burner control relay for closing said burner loop, a burner-control loop for energizing said burner control relay, a contact operable by pickup of the zone relay of said first zone to close said burner control loop through a branch loop, and a contact operable by pickup of the zone relay of said second zone to close said burner control loop through another branch loop.

14. A heating system as in claim 13 wherein said first zone is a basement.

15. A heating system as in claim 13 wherein said fanresponsive relay is connected across said fan.

16. A heating system as in claim 15 wherein said fan is switched by a thermostat responsive to the air temperature in the vicinity of said burner.

17. A heating system as in claim 13 wherein baflleposition-responsive switches are provided for inhibiting the sequence of events normally initiated by the respective zone relays of each said zone.

18. A heating system comprising a furnace having input and output ducts enabling air interchange between said furnaces and at least a pair of discrete zones of a dwelling; bafiie means within said ducts between each respective zone and said furnace, each said batfie means acmable to an activated position wherein the respective zone is in communication with said furnace, from a reset position wherein the respective zone is isolated from said furnace, actuator means for driving said baffle to said activated position, resetting means for returning said baflies to said reset position upon tie-energization of the respective said actuator, zone relays controlled by respective thermostats within said zones, a motoring loop for each said actuator to effect energization thereof, a respective starting loop for completing each motoring loop in response to energization of the zone relay of the respective zone, a respective holding loop bypassing each said starting loop, and means whereby each said holdmg loop is interrupted by any of all other zone relays which become energized.

1 9. A heating system as in claim 18 wherein a battleposition-responsive switch is provided in series with each said holding loop.

20. A heating system comprising a furnace having a burner, a burner loop for operating said burner, input and output ducts enabling air interchange between said furnace and at least a pair of discrete zones of a dwelling; a fan for efiecting said interchange, battle means within said ducts between each discrete zone and said furnace, each said bafile means actuable to an activated position wherein the respective zone is in communication with said furnace, from a reset position wherein the respective zone is isolated from said furnace, respective motor means for driving said bafiies to activated position, resetting means for returning said bafiles to reset position upon shutoff of the respective motor, zone relays operable by respective thermostats within said zones, a respective 1 1 1 2 motoring loop for energizing each said motor, a respectact operable by pickup of each zone relay to close said tive starting loop for completing each motoring loop, a burner-control loop through a respective branch loop. respective contact for each said starting loop for closing thereof upon pickup of the respective zone relay, 3 re- References Cited by the Examiner spective holding loop bypassing each said starting loop, 5 UNITED STATES PATENTS pickup of each zone relay efiective to open a contact in the holding loop of every other zone motor, a relay having 2244631 6/ 1941 Nessell 236*11 X a respective contact for effecting closure of each holding 2,271,487 1/1942 Nesseu 236 11 X loop during operation of said fan, a burner-control relay 2374514 2/1942 Nessen 236-11 X for closing said burner loop, a burner-control loop for 10 energizing said burner-control relay, and a respective con- EDWARD MICHAEL Prmary Exammer' 

1. A HEATING SYSTEM COMPRISING A FURNACE HAVING INPUT AND OUTPUT DUCTS ENABLING AIR INTERCHANGE BETWEEN SAID FURNACE AND AT LEAST A PAIR OF DISCRETE ZONES OF A DEWLLING; EACH SAID ZONE HAVING CORRESPONDING BAFFLES INTERPOSED BETWEEN ITSELF AND SAID FURNACE, BAFFLE OPERATING MEANS FOR SELECTIVELY ESTABLISHING OR PREVENTING SAID AIR INTERCHANGE BETWEEN ANY OF SAID ZONES AND SAID FURNACE, CONTROL MEANS FOR SAID BAFFLE OPERATING MEANS COMPRISING A THERMOPLASTIC SENSOR LOOP FOR EACH ZONE, A ZONE RELAY RESPONSIVE TO SAID SENSOR LOOP, MOTORING LOOP FOR EACH BAFFLE OPERATING MEANS TO DRIVE SAME IN RESPONSE TO ENERGIZATION OF THE RESPECTIVE ZONE-RELAY, A HOLDING LOOP FOR MAINTAINING SAID MOTORING LOOP AFTER DE-ENERGIZATION OF SAID ZONE-RELAY, AND DELAY MEANS TO BREAK SAID HOLDING LOOP AFTER SHUTDOWN OF SAID FURNACES, SAID MEANS RESPONSIVE TO COOLING OF SAID FURNACE. 